ABB RED650 Applications Manual page 111

1MRK 505 393-UEN B
Line differential protection RED650 2.2 IEC
Application manual
Protection functions in stations B and C operate as slaves (differential function
switched off) so currents are sent to protection function in station A, and received
on channels 2 and 3. To inform the differential algorithm that currents are coming
from the LV sides of the transformers, TraAOnInpCh must be set to 2 and
TraBOnInpCh to 3 (channel1 is reserved for local measurement). This is to ensure
that proper turn ratio and vector group correction is done.
Setting example with a three-winding transformer in the protected
zone
A
IED
IEC13000296 V2 EN-US
Figure 50: Three-winding transformer in the zone
Settings Station A
PDIF L3TCPDIF
NoOfUsedCTs
3
T raAOnInpCh 2
TraBOnInpCh
3
Currents from the secondary and tertiary windings of the power transformer are
connected to one line differential protection IED. Currents for each CT group are
sent to the IED at station A by the LDCM. To inform the differential algorithm that
currents are coming from the LV sides of the transformers, TraAOnInpCh must be
set to 2 and TraBOnInpCh to 3 (channel1 is reserved for local measurement). This
is to ensure that proper turn ratio and vector group correction is done.
Differential protection
T
T
Station B
L3TCPDIF
3
1
2
Section 6
B
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IEC13000296-1-en.vsdx
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